Pneumatic drill



Aug. 26, 1924,;

M. J. BURKEL PNEUMATI DRILL Filed Bim-eh 20. 119

6 Sheets-Sheet 1 fiile Aug. 26. 1924;

M. J. BURKEL PNEUMA'-IC DRILL und march 20. 191s 6 sheets-sheet 6 Sheets-Sheet 4,

Auge 26, E24;

M. J. EURKEL PNEUMATIG DRILL rund March 20, 1919 Patented Aug. 26, 1924.

UNITED STATES PATENT OFFICE.

MATHEW J'. BURKEL, OF AURORA, ILLINOIS, ASSIGNOR OF ON lit-FOURTH IO CLARENCE E. MEI-ILI-IOPE, 0F CHICAGO, ILLINOIS.

PNEUMATIC DRILL.

Application filed March 20, 1919.

To all wf/wm it may concern:

Be it known that I` MATHEW J. BURKEL, a citizen of the United States,l and a resident of Aurora, in the county of Kane and State of Illinois, have invented certain new and useful Improvements in Pneumatic Drills; and I do hereby declare that the following is a full, clear, and exact description thereof, reference being had to the accompanying drawings, and to the letters of reference marked thereon, which form a part of this specification.

This invention relates to improvements in pneumatic drills and consists of the matters hereinafter described and more particularly pointed out in the appended claims. 1

The objects as well as the several advantages of the invention, will appear more fully as I proceed with my specification.

In the drawings:

Figure l illustrates a vertical, longitudinal sectional view through a pneumatic drill embodying the invention, the plane of the section being indicated by the line 1 1 of Figure 3.

Figure 2 illustrates, on an enlarged scale,

a horizontal detail sectional view through a part of the improved pneumatic drill, the plane of the section being indicated by the line 2 2 of Figure 1.

Figure 3 illustrates a horizontal sectional view through the top cylinder casing, the plane of the section being indicated by the line 3 3 of Figure 1.`

Figures 4 and 5 illustrate vertical detail sectional views through air passageways in one of the cylinder casings, the planes of the sections being indicated by the lines 4 4 and 5 5 of Figure 3.

Figure 6 illustrates a top plan view of the gear case ring, with the top cylinder casing removed, a part of said gear case ring and the throttle valve being shown in section, to more clearly disclose the construction thereof.

Figure 7 illustrates, on an enlarged scale, a transverse section through the cylinders, on one side of the drill, and the valves for controlling the inlet and outlet of air to and from said cylinders, the plane of the section being indicated by the line 7 7 of Figure 3.

Serial No. 283,922.

Figures 8 and 9 illustrate views in side elevation as looked at from different angles, of one of the valves for controlling the inlet and outlet of air to and from one of the cylinders.

Figure 10 illustrates a transverse section through said valve, the plane of the section being indicated by the line 10 10 of Figure 8.

Figure 11 illustrates another transverse section through said valve, the plane of the section being indicated by the line 11 11 of Figure 9.

Figure 12 illustrates a vertical longitudinal detail sectional view through a modiiied form of driving gearing which may be interposed between the drill spindle and crank shaft, for driving the drill spindle at a speed relativelv lower than that shown in Figure 1.

Figure 13 illustrates a horizontal longitudinal section through the modified form of gearing shown in Figure 12 and the y plane of said section is indicated by the line 13 13 of Figure 12.

Figure 14 illustrates a vertical longitudinal sectional view through another modified form of driving gearing which may be interposed between the drill spindle and crank shaft, for driving the drill spindle at a speed relatively higher than that shown in Figure 1.

F igure 15 illustrates a horizontal longitudinal section through the modiied form of gearing shown in Figure 14 and the plane of said section is indicated by the line 3.5 15 of Figure 14.

rIhe improved drill has a casing comprising top and bottom cylinder parts and an intermediate gear case part, the said parts providing a vertical crank case, which eX- tends transversely through them. An inlet throttle is attached to one end of the gear case part and a diametrically opposed handle is attached to the other end of said gear case part. 20 and 21 indicate respectively, the top and bottom cylinder casing parts and 22 indicates the intermediate gear case part, of the casing as a whole. 23 indicates the throttle valve, and 24 indicates the opposed handle, which together with the throttle valve, provides the means for holding the drill during its operation.

The cylinder casing parts are identical and interchangeable, thus a description of one will suffice for both, the same numerals being used in each instance, the numeral used without the superfix indicating the top cylinder casing part, and the numeral used with the superix indicating the like parts of the bot-tom cylinder1 casing.

The cylinder casing consists of a shell having a bottom wall 25 which, as willv appear, provides a closure for the said casing. A vertical, hollow boss 26 rises from said wall and in said boss is formed a bore 27 forthe feed screw and spindle. 28, 29 indicate cylinders formed in said casing, which are arranged with their axes in a common horizontal plane and disposed at an angle divergent towards the throttle. end of the drill. Said cylinders embrace the space in which the boss 26 of the feed screw or spindle is located and intersect in a vertical line in the plane of the throttle and opposed handle of the machine, which line is indicated by the number 30 (see Figures 1 and 3). The said ,line of course is the vertical airis of the crank shaft.

The adjacent ends of the cylinders are formed to provide a crank casing 31, there being provided in line with'. each cylinder, openings closed by removable doors 32, 33 by means of which access may be had to said crank casing. On the adjacent sides of the cylinders and at either side of the bore 27, are formed valve chest bores 34, 35 arranged parallel to the screw bore and which open at each end through the said cylinder casing part. v y

The gear case part 22 consists of a flat, elongated ring having an annular, main, centrally disposed opening 36 in which is located the large driving gear for the spindle and a second smaller opening 37 located in the end Aofv said first named opening. The smaller opening 37 is arranged with its axis concentric with the axis of the crank casings of the cylinder casing parts 20, 21. The gear case ring 22 is provided with top and bottom, laterally extending, holed flanges 38, 38a and the base plates 25, 25 of the cylinder casings are provided with registering holes through which stud bolts 89 see Figure 7) extend for attaching thecylinder casings 20, 21 to said gear case ring 22. A centering hole 40 is formed through the base wall ends of each cylinder casing adjacent the throttle end of the drill and through the gear case v ring` in which is secured a main bolt 41. At the diametrically opposed ends of the cylinder casing ring are provided holes which register with holes in the ring 22, thro-ugh which taker stud bolts 42, 42a. These stud bolts,y together with the bolt 41, determine the alignment of the gear case ring and cylinder casings.

This construction is advantageous in that it provides for the use of identical cylinder casing parts which are of comparatively short vertical depth, so that there yis less tendency for the formation of blow holes in the casting of the casing. Also with said short casing parts there lis. less liability of shrinkage materially affecting or changing the essential dimensions of the same. With identical casing parts the machining will be more accurate and economical.

43 indicates the drill spindle and 44, the feed screw. The drill spindle has a recess 45 at its bottom end to receive the drill and a recess 46 at its top end to receive the bottom end of said feed screw. The vbottom end ofthe spindle 43 is journaled' in bearing bushings 47, v48 in the bore 27T:L of the bottom cylinder casing 21 andthe top end ofv said spindle is journaled in a third bearing bushing in the bore 27 yof the ltop cylinder casving 20. y

In the main central opening 36 of the gear case ring 22 is located the'main gear 5() y which is keyed to the drill spindle as clearly shown in Figure l. Said gear has a hub 50a onits bottom end 'which engages aga-instan annular shoulder 51 on the drill spindle, said parts providing a thrust bearing on the one side for said spindle. On the top end of the 50 is located an antifriction thrust bearing, indica-ted as a whole by the numeral 52, which engages with an annular shoulder 53 formed in the bore 27 in the top cylinder casing 20. It will be noticed from the drawings that no change is required in the bores 27, 27ZL of the top and bottom cylinder cas-y ings', toi/receive the bearing bushings as above described.

In 'the top end of the bore 27 is a feed screw sleeve 55 held in place by means of a Iiamb nut l56, through which the feed screw 44 has threaded bearing in a familiar manner.

ln order to lock the feed screw 44 against any uiiscrewing movement during the operation or use of the tool, I provide a tension device, as illustrated in Figures 1 and 2.

Said tension device consists of a yielding block 57a located in a'slot in the feed screw sleeve 55, disposed radially with respect to the feed screw. gaged with the threads of the feed screw and is held in engagement with the said screw by i'neans of a single coiled spring 58 arranged in an eccentric groove 58EL formed in the feed screw sleeve. The said block 57a preferably has another function, in that itacts to limit the outward unscrewing movement of the feed screw. It performs this function in connection with arecess 44a, defining a shoulder ySaid block has--teeth 57b en- ,l

at the bottom en d of the feed screw, and with which it is brought into engagement by the spring 56 when the screw is brought into position where said block may be caused toengage said recess. This locks the feed screw against further withdrawal. This co-nstruction permits of the use of a single, long, nontelescopic feed screw which cannot unscrew itself through the feed screw sleeve and cannot be withdrawn from said sleeve by reason of said block 57a and recess 1451.

Passing now to a more detailed description of the cylinders and pistons-each of the cylinders is open at its outer end and is provided with an internal thread in which is engaged an associated head, 59, 60, and 59a, 60a indicating said heads. The pistons are all alike and are connected to the crank shaft in the same manner so that a description of one will suiiice for all. 61 indicates the piston, and 62 indicates its associated connecting rod. 63 indicates the crank pin of the crank shaft to which it is attached. The piston 61 has a socket 64 in which is engaged a ball head 65 on one end of the connectingv rod. The opposite end of the pitman is connected by a strap 66 to the crank pin 63. Said strap is substantially U-shaped, is preferably made of wrought iron, and is bolted at its ends to each side of the connectingrod and engages on the crank pin by means of a split bushing 67 located in an opening 68 iu the crank end of the connecting rod. As the cylinders in each case are in the same plane, the straps 66 at their crank pin ends are made, one with tongue formation and the other witha fork formation, in a familiar way, so that both pitmen may be located in the same plane. It will be noticed that the shoulder' construction between the connecting rod and strap, take all end thrust off of the coacting screws, so that there is no danger of shearing off said screws which would permit of said strap and connecting rods coming' apart. y

70 indicates the crank shaft as a whole. Said shaft consists oftwo like parts 71 and 71a. Each part consists of a crank arm 72, 7 a liXed to the outer end, namely the top or bottom end of its associated crank pin 63, 63l of a crank stub 73 73a fixed to the outer end, that is to say, the top or bottom end of said crank arms; and of a crank disc 74 74a fixed to the inner end, that is to say, the bottom or top end of its associated crank pin, all as clearly illustrated in Figure 1.. The crank stubs 73 73n have bearing in bosses 75 75il in the associated cylinder casings, ball bearings 76 76a being provided in said bosses for directly supporting said crank stubs. The crank discs 74 7aa have bearing in the base walls of the associated cylinder casings. ball bearings 77 77a being provided, the same being supported by rings 78 78EL engaged between opposed shoulders 79 and 80, formed respectively in the base walls of the cylinder casings and adjacent the faces of the gear case ring. The two parts of the crank shaft are connected together by a pin 81y in line with the stub shaft parts 73, 73a which pin has a broached connection with said discs, said pin being flattened on one side and driven into an opening somewhat smaller but of the same form, in said discs. On the pin are formed gear teeth 82 which mesh with the main driving gear 50 of the spindle, and to insure a rigid connection between pin and the cra-nk discs, the discs are provided with openings adapted to receive the parts 82X of the teeth which are preferably somewhat radially shorter than the main teeth. This provides an absolutely rigid connection between the pin and the crank discs and permits of the use of a crank shaft having a four point bearing, wherein power is delivered to the ends of the same and is given olf at the middle of the same so that torsional strain is practically eliminated.

The valves for controlling the inlet to and exhaust from'the cylinders are rotary valves. Each valve consists of a plug (see Figures 7, 8 and 9) mounted in its associated valve bore 34C, a bushing 91 being provided between the bore and the valve proper. The valve bores, as before stated, are open at their outer ends and are threaded to receive a cap or `head 92. The valve plugs are each retained within their associated bores by means of a spring ring 93 which engages in an annular groove in the bushing and abuts against a shoulder 95 on the plug.

The valve plug 90 has a central opening 96 through it, said opening being closed at the bottom by an integral part of the plug and being closed at the top by means of a threadled plug 97. At about the middle of the bore in the plug there is provided another threaded plug 98 which acts to divide the bore into -two parts. Above and below the intermediate plug 98 are formed annular grooves 99 and 100. One of these is an inlet groove and the other an outlet groove, depending on Whether the drill is running in one direction or the other. Ports 101 and 102 connect said grooves with the two parts of the interior bore 96 in the valve plug. In the intermediate body of the plug are provided opposed vertical grooves 103, 10-1 (which are about 60O in arcuate extent). The bottom of one of said grooves opens through a slot 105, into the bore of the valve plug just below the intermediate plug 98 `and the top of the other groove 104 opens through a slot 106 just above said intermediate plug. The grooves 103, 104 with their associated slots, in connection with a slot in each bushing. provide the communication between the valve plug and the associated cylinder, while the annular grooves 99 and 100 with their associated Jorts in connection with revisterin(y o enings in each bushing, provide communication between the bore of the valve plug and the throttle valve 23 before mentioned.

Intermediate the two valve bores of each cylinder casing are located and formed top and bottom, arcuate, connecting air chambers 108 and 109. The top chamber 108 communicates with the top grooves 99 of both valve plugs in the cylinder casing, while the bottom chamber 109 communicates with the bottom grooves of both valve plugs 'of vsaid cylinder casing. On the top of the casing are provided hollow bosses 110 and 111. Tn the first is provided a passage 112 connecting with the top air chamber 108 and -in the vsecond is provided a passage 113 connected with the bottom chamber 109. Each of these passages connects with an associated` passage 114, 115 respectively, formed in the gear case ring 22 which in turn connects with the throttle valve 23', as will presently be described. v

The valve plugs 90 each project at their inner ends beyond associated bores in the cylinder casings, into a position within the gear case ring 22, and on each inner` end is provided a gear pinion 116. At the top and bottom of the main gear 50 before mentioned, which is preferably flanged to receive them, are provided internal gear rings 117 which engage and drive the pinions 116 on the several valve plugs, at a predetermined rate compared to the drive of the crank shaft 78.v This ratio is one to one with reference to said crank shaft. y

Then the passage 114 in the gea-r case ring acts as an inlet, the other passage 115 acts as an exhaust, and vice versa, according to whether the drill spindle is rotating forward or reverse. When the passage 114 is acting as an inlet and the passa-ge 115 is acting as an exhaust, the passage 112 in the hollow boss 110 of the top cylinder casing, which communicates with the passage 114, will feed live air to the top chamber 108 and the passage 113 which communicates with. the passage 115 will conduct exhaust air from the bottom chamber 109. The passages in the bottom cylinder casings corresponding to the passages 112, 113 of the top cylinder casing will be the op posite by reason of the reversed position of the bottom cylinder casing, so that the chamber 109a of said bottom cylinder casing will be the inlet air chamber and the chamber 108n will be the exhaust chamber'. Vhen the passage 115 is the live air passage and the passage 114 is the exhaust air pas sage, the functions of the chambers 108-109 and 109L and 108a will be reversed.

Assuming now that the air chambers 108 and 109L are the inlets and the chambers 109 and '1()8L are the exhausts, it will be noticed that the slot 105 in the top valve plug 90 in Figure 7 is in a position wherein exhaust air from the cylinder 28 passes through said slot into the inner end of the chamber 96 and then through the holes 102 and groove y100 into the exhaust chamber 109 of the.

top cylinder casing. Vhile the air is thus exhausting, the hve air in the chamber 108 enters and fills the outer end part of the chamber 96 and thus the pressure builds up therein to equalize not only the end pressure of the exhaust on the valve plug but valso the side pressure therein so that the pressures are balanced on each side of the middle plug 98 of said valve plug. Thus, there is no end pressure or side pressure to causea grinding or sticking of the valve plug in its bushing. i

Vhile the cylinder in the top casing 20 is exhausting, live air from the chamber 108* in the bottom casing 21 willpass through the groove 99 vand holes 101 in the bottom valve plug into the outer end lof the chamber 96 and then through the slot 106 and groove 104 into the bottom cylinder 28a and impart a power stroke to the piston therein. Thus it will be noticed thatwhile the cylinders 28 and 29a of both cylinder casings are jointly acting as exhaust cylinders, the other cylinders 28a and 29 lare jointly acting as the inlet or power cylinders. In the rotation of the valves bythe internal gears 117, the inner and outer ends v of the chamber 96 in each valve plug will be alternately brought into and out of `register' with the associated cylinder on the in and out strokeof the associated piston.

Vith the valve structure as above ydescribed, an easy tin'iing of said valves with respect to their associated pistons and cylinders is provided because they may be entered through the outer end of theirl respective bores after the pistons have been assembled in their associated cylinders and may be set with precision with respect to said pistons before the pinions on their inner ends are engaged with their driving gears. Furthermore, as before described, by reason of the balanced pressure on said valve plugs, there will be no friction to overcome due to end or side thrust of said valve plugs.

The construction of the throttle valve 28 is as follows :-In the front extension of the gear case ring 22 is formed a vertical opening 118 in which a rotatable valve plug 119 is mounted, a valve bushing 120 being provided in said opening to directly receive the valve. :Into ,the extension 121 is threaded ai tube 1212, the outer end. of which receives a :threaded nipple 123 by means of which an air hose connection-may be made to the tube. A sleeve 124 is rotatively mounted on the tube 122 and is vprovided at its inner end with a segmental beveled gear 125. Said gear engages with a segmental gear 126 on the top end of the valve plug 119. Thus by ro-` tating the sleeve 124, thevalve plug may be rotated and by means of this rotation will serve to drive the tool in one direction or the other. The valve plug 119y is providedy with a transverse, horizontal passageway 127 and at t-he Asides kthereof are` provided downwardly opening pockets 128, 128. In the valve bushing 120` are formed ports, namely a main inletk port 129 and ports 130, 131, the latter having passageways 114a 115a which connect with the ports 114 and 115 heretofore referred to. Below. the valve plug and arranged in a plane transverse to the axis thereof, is a deflector plate 132 which has a flange offset 133 by means of which it is attached to the bottom of the gear case ring extension `121. The valve plug 119 has a bottom stem 119a which extends through an` opening in the deflector plate 132 and a nut 119'3, threaded on said stem below said deflector plate, acts to yieldingly hold said valve plug to its seat.

A vent tube 134 is located in the hole 37 of the gear case ring with its ends projecting through holes 135 in the face ofsaid ring and in said tube itself are perforations 136. By means of this tube, the 'interior of the casing as a whole, is properly vented without the danger of the lubricant being blown out through said tube.

In Figures 12 and 13 lis shown a modification of the spindle driving gearing, which is adapted to drive the spindle at a speed lower than that of the crank shaft. In said Figures 12 and 13, all parts except the spindle driving gearing, are indicated by the same numerals as heretofore, there being no change in said parts except that the gear case ring is made a little deeper. In this case, 137 indicates a large gear driven by the gear 82 on the crank shaft. Said gear consists of a top plate or body 138 having a depending flange 139 on which the gear teeth are formed, the plate being keyed as indicated at 140 to a gear 141 loosely mounted on the drill spindle. A second gear including a plate 143 spaced below the plate 138 of the first named gear and having a hub 144, is keyed asy indicated at 145 to the drill spindle. The plate 143 has a flange 146 which extends upwardly within the flange 139 of the other gear, and which is provided on its inner surface with an internally geared ring 147, which is keyed to it as indicated at 148.

In the space between the two plates 143 and 138, planetary gears 149 are mounted on studs 150 carried by and depending from the plate 138 of the first-named gear, and which are engaged on the one side with the teeth on the gear ring 147, and on the other side of the gea-r 141 that is loose on the spindle. Manifestly by this construction the spindle is driven at a lower rate of speed than the crank shaft.

In Figures 14 and 15 is illustrated a gear for driving the spindle at a speed higher than that of the crank shaft. In this case, 151 indicates the gear that is keyed to the spindle. This gear has a long hub 152 (153 indicating the key by means of which it is fixed to the spindle), and a T-shaped web 154 on which the teeth are carried. 155 indicates as a whole, a large gear loosely mounted on the hub 152 of the spindle gear and enga-ged with the gear on the crank shaft. The gear 155 consists of top and bottom parts or plates 156, 156, having hub parts 157, 158 which are mounted on the spindle gear hub 152 and which engage within the T-shaped web 154 of said'gear. 159 indicates planetary gears carried on studs 160 which connect the two parts of the gear 155 together. Said planetary gears engage withy an internally geared ring 161 fixed within the gear opening in the gear ring, by means of a key 162. Manifestly this gearing will drive the spindle at a higher speed than that of the crank shaft.

By the construction above described, it will be noted that the top and bottom cylinder casings may be used with gear case rings of different vertical depths so that no change is required in the cylinder casings, when a compound spindle driving gearing is provided instead of the direct drive as shown in Figure. 1.

I claim as my invention:

1. A pneumatic drill comprising a flat gear case ring, top and bottom cylinder casings fixed to said ring, pistons in said cylinder casings, an upright drill spindle journaled at its ends in said cylinder casings, a crank shaft parallel with the spindle and journaled in the cylinder casings, said crank shaft extending through the gear case ring and being driven by said pistons, a toothed member in said gear case ring operatively connected to the drill spindle and driven by said crank shaft, top and bottom internal gears mounted on said toothed member, and upright rotary valves having gear pinions on their inner ends meshing with said vinternal gears, said valves controlling the inlet and discharge of pneumatic uid to and from the piston cylinders.

2. A pneumatic drill comprising a fiat gear case ring having air inlet and exhaust ports, a valve plug in said ring for controlling the inlet and exhaust of air to and from said ports, top and bottom cylinder casings fixed to said ring, each casing having air passageways communicating with said cylinders and with said inlet and exhaust ports in said ring, pistons in said cylinder casings, an upright drill spindle journaled at its ends in said cylinder casings, a crank shaft parallel with the sp-indle and journaled in the cylinder casings, said crank shaft extending through the gear case ring and being driven by said pistons, a toothed member in said gear case ring, operatively connected to the drill spindle and driven by said crank shaft, top and bottom internal gears mounted on said toothed member, upright rotary valves in said cylinder casing air passageways, each valve havingv a gear pinion on its inner end mesh ing with said internal gears, said valves controlling the inlet and exhaust of air to and from the piston cylinders.

i 3. A. pneumatic drill comprising a casino having a plurality of horizontally disposed piston cylinders andy vertically disposed valve chest bores, one associated With each cylinder, said casing also having .top and bottom air passageways communicating with said valve chest bores, a rotary valve plug in each bore, each valve plug having inner and outer, separated chambers, adapted in the rotation of the valve plug to be brought alternately into communication With ,the piston cylinder and bottom air passageway and the piston cylinder'and top air passageway respectively, said valve plugs each having a pinion at its Vinner end, a crank shaftjournaled in the casing and actuated by the piston, a drill spindle journaled in the casing, a member operatively connecting saidl drill spindle to said crank shaft, and gear rings carried by said member and meshing with the pinions on the inner end of the cylinders, a .valve plug for controlling the inlet and exhaust of a pneumatic vfluid tov and from the cylinders, said valve plugcoinprising acylindrical body closed at its top and bottom ends, and havingvr two separated chambers between said ends, there being air ports entering through the, ends of the body into the outer ends of said chambers, and there being dia-nietrically opposite ports arcuately spaced ap-art, communicating withl the inner ends of said chambers, said valve body being provided atl one of its closed ends With a. gear pinion. p

In testimony that I cla-im the foregoing as myv invention, I affix my signature in the presence of two "Witnesses, this 18th dayy Y of March, A. D., 1919. f f I l 'MATHEW J. BURKEL.

Witnesses v: l

T. H. ALFREDS, D. DARRENOUGUE. 

